1. Field of the Invention
The instant invention relates to a well string section spinning tool incorporating a pair of endless well string section engaging drive belts each including a positive bight extending about and frictionally engaged by at least approximately 180.degree. of the outer peripery of a drive wheel or drum and with each drive belt further passing about three guide rollers arranged relative to the well string section to be spun such that an inverse or negative bight of each drive belt extends about and frictionally engages at least 270.degree. and less than 360.degree. of the outer periphery of the well string section and with the 270.degree. peripheral areas of the well string section engaged by the inverse bights of the belts overlapping each other by at least generally 90.degree.. By such engagement of a well string section to be spun throughout the equivalent of 540.degree. of the outer periphery of the well string section rotary torque applied to the well string section through the drive belts may be dramatically increased above the usual drive torque transferable from drive belts to a well string section to be spun, this being extremely important when drive belts as opposed to drive chains are used to prevent the outer surfaces of a metallic well string section from being marred and when relatively fragile fiberglass or similar other than metallic well strung sections are to be spun.
2. Description of the Related Art
Well string spinning tools including some of the general structural and operational features of the instant invention are disclosed in my prior U.S. Pat. No. 4,471,674 and in U.S. Pat. No. 4,512,216. In addition, other similar well string section spinning tools are disclosed n U.S. Pat. Nos. 870,014, 1,105,854, 1,925,970, 2,365,839, 2,487,987, 2,523,159, 2,690,689, 2,746,329, 2,862,690, 4,099,429 and 4,099,430.
However, these prior patents do not disclose well string section spinning tools including the increased drive belt-to-well string section torque transfering capacity of the well string section spinning tool of the instant invention.